Three currently manufactured thrust bearings which have means for retaining a cage and roller assembly within a thrust bearing race are known as formed tabs, full 360.degree. curl and banding. The U.S. Pat. No. 3,900,235 dated Aug. 19, 1975 to Richard L. Alling et al and entitled "Tab Race" describes a thrust bearing with a race having formed tabs to retain the cage and roller assembly. The U.S. Pat. No. 3,913,994 dated Oct. 21, 1975 to Richard Alling et al and entitled "Bearing Offset Lip Cage" describes, among other things, a full 360.degree. curl for retaining the cage and roller assembly. The U.S. Pat. No. 4,174,138 dated Nov. 13, 1979 to Dean E. Johnston and entitled "Thrust Bearing and Separator" describes a thrust bearing including a band for retaining the cage and roller assembly.
Several problems are associated with the formed tab. The press tooling is complex and must be run slowly. The tooling requires a good deal of maintenance. The dimensions of the tabs are difficult to maintain. Improper tabs can result in poor retention, interference with the bearing performance, or damage to the bearing when it is being assembled. These problems, when combined, result in a relatively high scrap rate.
The problems associated with the full 360.degree. curl are the same as the formed tab, however, the dimensional tolerances are not quite as tight. The problems associated with the banded assemblies include the high cost of manufacturing one or two additional components, the added inventory, and assembly problems.